Draft:Long-snouted African spurdog

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The Long-snouted African spurdog (Squalus bassi) is a species of dogfish shark belonging to the genus Squalus. It was formally described in 2017 by S. T. de F. L. Viana, M. R. de Carvalho, and D. A. Ebert in a paper reviewing earlier data of the Squalus group in southern Africa. After comparing previous morphological records for the first time, the authors concluded that the specimens represented a distinct species rather than a subspecies of Squalus blainvillei or Squalus mitsukurii, distinguishing the previous ambiguous relationship.[1]

This species exists around the coast of South Africa, with a probable range extending across the south-eastern Atlantic and the western Indian Ocean. It inhabits tropical marine environments and has been recorded from pelagic to neritic zones. Most known specimens were collected from South Africa and Mozambique, such as the outer shelf and upper continental slope and the Western Cap around the Agulhas Bank.[2]

The Long-snouted African spurdog has a grey dorsal surface and a body morphology described as fusiform, in a relatively robust shape. The holotype adult male measures about 0.68 meters in length, while females are generally slightly larger, making it one of the smaller members in the Squalus genus. Taxonomically, it belongs to the class Chondrichthyes, order Squaliformes, family Squalidae, and genus Squalus.[3]

In its native region, the species is also known in Afrikaans as “Langneus-penhaai.” The Latin species name “bassi” is in order to honor the former shark specialist, Alan John Bass, for his contributions to shark taxonomy and systematics.[4]

Description

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Long-snouted African spurdog (Squalus bassi) is a small, robust species of spurdog shark. It has a streamlined body with a broad head and an elongated, rounded snout, which is one of its distinctive features. The dorsal surface is generally gray, while the underside lighter. The eyes are large and oval in shape. This species has two dorsal fins, each bearing a spine, with the second spine longer than the first. The pectoral fins are narrow and elongated, and the upper lobe of the caudal fin is relatively long and nearly rectangular. Its body is covered with small, tricuspid dermal denticles that give the skin a rough texture.[5]

Within its genus, Long-snouted African spurdog is considered a relatively small species. The holotype male measures 683 mm in total length, with females generally being slightly longer. Recorded maximum total lengths reach 960 mm for males and 1100 mm for females. The smallest mature individuals measure 650 mm for males and 730 mm for females.[6]

The back of Long-snouted African spurdog is dark gray to brownish gray, fading to a pale ventral surface. The first dorsal fin is dark brown with a whitish base, while the second dorsal and caudal fins have faint whitish margins near their edges. The upper caudal margin is white near the base, and the lower postventral margin is also white. This species lacks a distinct black caudal bar, distinguishing it from several close species.[7]


Juveniles differ slightly in both color and body size. Their bodies are generally brown or light brown, with black tips on the dorsal fins. A dark blotch can be seen at the base of the caudal fin, while the lower lobe mostly white. Newborn Long-snouted African spurdog measure about 210–300 mm in length, while juveniles range from 0.3 to 0.5 m, and adults about 0.6 to 0.9 m.[8]

S. bassi is often confused with S. mitsukurii, S. blainvillei, and S. montalbani. Compared to S. mitsukurii, S. bassi has a more rectangular upper caudal lobe with a shallower fork and more rounded tips. It differs from S. blainvillei by its grayer coloration rather than reddish-brown tone and by having a proportionally longer head. From S. montalbani, it can be distinguished by the position of its pelvic fins, which lie midway between the two dorsal fins rather than closer to the second. Although few genetic studies have compared these species, morphological evidence supports it as a distinct species.[9][10][11][12]

Classification

[edit]

The Long-snouted African spurdog (Squalus bassi) belongs to the class Chondrichthyes, subclass Elasmobranchii, order Squaliformes, family Squalidae, and genus Squalus.The genus Squalus comprises several different but morphologically similar long-snouted dogfish species, distributed across temperate and tropical oceans. S. bassi could be most closely related to the Japanese spurdog (S. mitsukurii) and the Longnose spurdog (Squalus blainville), but it is currently recognized as a distinct species based on morphological differences.[13]

Distribution

[edit]

The Long-snouted African spurdog is known to appear along the coasts of South Africa, including the south-eastern Atlantic and western Indian Oceans. The holotype was collected from the outer shelf and upper continental slope near Agulhas Bank, Western Cape, South Africa, at a depth of about 201 m. Additional paratypes were obtained from several localities along the west and east coasts of South Africa, as well as from Mozambique, while the species inhabits water depths ranging from pelagic to neritic zones.[14]

Based on current data, Long-snouted African spurdog is relatively common in the Western Cape region of South Africa, roughly between 29° and 32° S. A few records have also been reported from St. Francis Bay in the Eastern Cape and from the coast of Mozambique. Earlier studies suggested its possible presence northwest of the Orange River off Namibia, though this has not been confirmed.[15]

Members of the order Squaliformes are typically found on outer continental shelves and upper slopes throughout the world’s oceans, especially in temperate and tropical regions.[16] Like other members of the order Squaliformes, Long-snouted African spurdog inhabits those reigions, at depths between 159 and 591 m, with an average around 300 m. The species could be dedicated to favor warm to tropical deepwater environments with sandy or muddy bottoms, according to the habits of other spurdogs, which includes upwelling zones and nutrient-rich waters that could support diverse benthic communities.[17] These environmental conditions possibly also provide suitable habitats for Long-snouted African spurdog.[18]

No population density or abundance data are currently available for Long-snouted African spurdog, but collection records indicate that it is relatively common along the southern coast of South Africa, while its presence in other areas remains uncertain.[19]

Life history

[edit]

The Long-snouted African spurdog has a relativity broad diet, feeding mainly on bony fishes, cephalopods, and crustaceans.[20] It can be considered a mid-level predator within deep demersal communities[21], which is consistent with the general feeding habits observed across the genus Squalus.[22][23][24]

Data from previous ecological studies shows Long-snouted African spurdog might have migration behavior[25], however, both of the old study data of reproduction and phylogeography of Long-snouted African spurdog could be mixed with other Squalus species from southern Africa. Further dedicated research is needed to clarify its ecology.[26]

Available data indicate that Long-snouted African spurdog is a viviparous species[27], similar to other members of the genus.[28] Females give birth to approximately 4–9 newborns per time, with newborns measuring around 210–300 mm in total length and the smallest free-swimming individuals recorded at 230–235 mm.[29]

Because the Long-snouted African spurdog is a recently described and newly differentiated species, many aspects of its biology remain unresearched, including it's population structure, populationsize, reproductive cycle, age, or growth rate.[30] Based on comparisons with related species, Squalus species are generally yolk-sac viviparous, with long reproductive cycles, and gestation periods that may exceed one year. They typically exhibit slow growth and long lifespans, traits that result in low population productivity and highlight the possible need for attention to conservation and management of Long-snouted African spurdog populations.[31][32]

Conservation status

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At present, very little information is available regarding the conservation status, potential threats or other information about the Long-snouted African spurdog. Since the species was only formally described and recognized as distinct in 2017, it has not yet been assessed by the IUCN Red List, and no studies have examined its population trends, distribution stability, or exposure to fishing pressure.[33]

Long-snouted African spurdog appears to have no known cultural or economic significance, and has not been identified as a targeted fishery resource. Overall, the ecological relationship between this species and human activities remains largely unknown.[34]

However, from a broader perspective, many members of the genus Squalus have long been taken as bycatch in deep-sea trawl, longline, and demersal fisheries.[35][36] In some areas, these sharks are also caught intentionally for the shark fin trade, or out of fear of attacks on humans.[37] Their meat is used locally for food, fishmeal production, or traditional medicine, which could be an important source for in developing regions such as Africa.[38] As mentioned above, this genus is generally characterized by slow growth, late maturity, and low fecundity, making overfishing a significant threat to population recovery. [39][40]

Environmentally, rising ocean temperatures and decreasing oxygen levels linked to climate change may alter deep-sea ecosystems, affecting prey availability and suitable habitat for sharks.[41] Deep-sea fishery expansion and marine pollution could also pose additional threats. [42]

References

[edit]
  1. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  2. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  3. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  4. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  5. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  6. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  7. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  8. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  9. ^ Viana, Sarah T. De F.; Carvalho, Marcelo R. De; Gomes, Ulisses L. (4 July 2016). "Taxonomy and morphology of species of the genus Squalus Linnaeus, 1758 from the Southwestern Atlantic Ocean (Chondrichthyes: Squaliformes: Squalidae)". Zootaxa. 4133 (1): 1–89. doi:10.11646/zootaxa.4133.1.1. PMID 27395700.
  10. ^ De F. Viana, Sarah T.; De Carvalho, Marcelo R. (July 2016). "Redescription of Squalus acutipinnis Regan, 1908, a Valid Species of Spiny Dogfish from Southern Africa (Chondrichthyes: Squaliformes: Squalidae)". Copeia. 104 (2): 539–553. doi:10.1643/CI-14-217.
  11. ^ de F. L. Viana, Sarah T.; Lisher, Mark W.; de Carvalho, Marcelo R. (December 2018). "Two new species of short-snouted dogfish sharks of the genus Squalus Linnaeus, 1758, from southern Africa (Chondrichthyes: Squaliformes: Squalidae)". Marine Biodiversity. 48 (4): 1787–1814. Bibcode:2018MarBd..48.1787D. doi:10.1007/s12526-017-0673-8.
  12. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  13. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  14. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  15. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  16. ^ Compagno, L. J. V.; Ebert, D. A.; Cowley, P. D. (December 1991). "Distribution of offshore demersal cartilaginous fish (Class Chondrichthyes) off the west coast of southern Africa, with notes on their systematics". South African Journal of Marine Science. 11 (1): 43–139. doi:10.2989/025776191784287664.
  17. ^ Dell’Apa, Andrea; Bangley, Charles W.; Rulifson, Roger A. (1 June 2015). "Who let the dogfish out? A review of management and socio-economic aspects of spiny dogfish fisheries". Reviews in Fish Biology and Fisheries. 25 (2): 273–295. Bibcode:2015RFBF...25..273D. doi:10.1007/s11160-014-9379-1.
  18. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  19. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  20. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  21. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  22. ^ Dell’Apa, Andrea; Bangley, Charles W.; Rulifson, Roger A. (1 June 2015). "Who let the dogfish out? A review of management and socio-economic aspects of spiny dogfish fisheries". Reviews in Fish Biology and Fisheries. 25 (2): 273–295. Bibcode:2015RFBF...25..273D. doi:10.1007/s11160-014-9379-1.
  23. ^ Braccini, J. Matías; Gillanders, Bronwyn M.; Walker, Terence I. (1 January 2005). "Sources of variation in the feeding ecology of the piked spurdog (Squalus megalops): implications for inferring predator–prey interactions from overall dietary composition". ICES Journal of Marine Science. 62 (6): 1076–1094. Bibcode:2005ICJMS..62.1076B. doi:10.1016/j.icesjms.2005.04.004.
  24. ^ Ebert, D. A.; Compagno, L. J. V.; Cowley, P. D. (1 June 1992). "A preliminary investigation of the feeding ecology of squaloid sharks off the west coast of southern Africa". South African Journal of Marine Science. 12 (1): 601–609. doi:10.2989/02577619209504727.
  25. ^ Dell’Apa, Andrea; Bangley, Charles W.; Rulifson, Roger A. (1 June 2015). "Who let the dogfish out? A review of management and socio-economic aspects of spiny dogfish fisheries". Reviews in Fish Biology and Fisheries. 25 (2): 273–295. Bibcode:2015RFBF...25..273D. doi:10.1007/s11160-014-9379-1.
  26. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  27. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  28. ^ Dell’Apa, Andrea; Bangley, Charles W.; Rulifson, Roger A. (1 June 2015). "Who let the dogfish out? A review of management and socio-economic aspects of spiny dogfish fisheries". Reviews in Fish Biology and Fisheries. 25 (2): 273–295. Bibcode:2015RFBF...25..273D. doi:10.1007/s11160-014-9379-1.
  29. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  30. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  31. ^ Faure-Beaulieu, Nina; Lombard, Amanda T.; Olbers, Jennifer; Goodall, Victoria; da Silva, Charlene; Daly, Ryan; Jordaan, Gareth; Kerwath, Sven E.; Kock, Alison; Mann, Bruce Q.; Murray, Taryn S.; Albano, Patricia; Cliff, Geremy; dos Santos, Natalie A.; Gennari, Enrico; Hammerschlag, Neil; Bester-van der Merwe, Aletta E.; Watson, Ralph; Andreotti, Sara; Bernard, Anthony T. F.; Cowley, Paul D.; De Vos, Lauren; Drobniewska, Natalia; Elston, Chantel; Fallows, Chris; Rogers, Toby D.; Smith, Grant; van Staden, Michaela; de Villiers, Pierre; Paulet, Timothy Guy; Harris, Jean (1 August 2023). "A systematic conservation plan identifying critical areas for improved chondrichthyan protection in South Africa". Biological Conservation. 284 110163. Bibcode:2023BCons.28410163F. doi:10.1016/j.biocon.2023.110163.
  32. ^ Dulvy, Nicholas K.; Simpfendorfer, Colin A.; Davidson, Lindsay N. K.; Fordham, Sonja V.; Bräutigam, Amie; Sant, Glenn; Welch, David J. (5 June 2017). "Challenges and Priorities in Shark and Ray Conservation". Current Biology. 27 (11): R565 – R572. Bibcode:2017CBio...27.R565D. doi:10.1016/j.cub.2017.04.038. PMID 28586694.
  33. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  34. ^ Viana, S. T. de. F. L.; de Carvalho, M. R.; Ebert, D. A. (2017). "Squalus bassi sp. nov., a new long-snouted spurdog (Chondrichthyes: Squaliformes: Squalidae) from the Agulhas Bank". Journal of Fish Biology. 91 (4): 1178–1207. Bibcode:2017JFBio..91.1178V. doi:10.1111/jfb.13448. PMID 28905386.
  35. ^ Dulvy, Nicholas K.; Simpfendorfer, Colin A.; Davidson, Lindsay N. K.; Fordham, Sonja V.; Bräutigam, Amie; Sant, Glenn; Welch, David J. (5 June 2017). "Challenges and Priorities in Shark and Ray Conservation". Current Biology. 27 (11): R565 – R572. Bibcode:2017CBio...27.R565D. doi:10.1016/j.cub.2017.04.038. PMID 28586694.
  36. ^ Faure-Beaulieu, Nina; Lombard, Amanda T.; Olbers, Jennifer; Goodall, Victoria; da Silva, Charlene; Daly, Ryan; Jordaan, Gareth; Kerwath, Sven E.; Kock, Alison; Mann, Bruce Q.; Murray, Taryn S.; Albano, Patricia; Cliff, Geremy; dos Santos, Natalie A.; Gennari, Enrico; Hammerschlag, Neil; Bester-van der Merwe, Aletta E.; Watson, Ralph; Andreotti, Sara; Bernard, Anthony T. F.; Cowley, Paul D.; De Vos, Lauren; Drobniewska, Natalia; Elston, Chantel; Fallows, Chris; Rogers, Toby D.; Smith, Grant; van Staden, Michaela; de Villiers, Pierre; Paulet, Timothy Guy; Harris, Jean (1 August 2023). "A systematic conservation plan identifying critical areas for improved chondrichthyan protection in South Africa". Biological Conservation. 284 110163. Bibcode:2023BCons.28410163F. doi:10.1016/j.biocon.2023.110163.
  37. ^ Dulvy, Nicholas K.; Simpfendorfer, Colin A.; Davidson, Lindsay N. K.; Fordham, Sonja V.; Bräutigam, Amie; Sant, Glenn; Welch, David J. (5 June 2017). "Challenges and Priorities in Shark and Ray Conservation". Current Biology. 27 (11): R565 – R572. Bibcode:2017CBio...27.R565D. doi:10.1016/j.cub.2017.04.038. PMID 28586694.
  38. ^ Dulvy, Nicholas K.; Simpfendorfer, Colin A.; Davidson, Lindsay N. K.; Fordham, Sonja V.; Bräutigam, Amie; Sant, Glenn; Welch, David J. (5 June 2017). "Challenges and Priorities in Shark and Ray Conservation". Current Biology. 27 (11): R565 – R572. Bibcode:2017CBio...27.R565D. doi:10.1016/j.cub.2017.04.038. PMID 28586694.
  39. ^ Faure-Beaulieu, Nina; Lombard, Amanda T.; Olbers, Jennifer; Goodall, Victoria; da Silva, Charlene; Daly, Ryan; Jordaan, Gareth; Kerwath, Sven E.; Kock, Alison; Mann, Bruce Q.; Murray, Taryn S.; Albano, Patricia; Cliff, Geremy; dos Santos, Natalie A.; Gennari, Enrico; Hammerschlag, Neil; Bester-van der Merwe, Aletta E.; Watson, Ralph; Andreotti, Sara; Bernard, Anthony T. F.; Cowley, Paul D.; De Vos, Lauren; Drobniewska, Natalia; Elston, Chantel; Fallows, Chris; Rogers, Toby D.; Smith, Grant; van Staden, Michaela; de Villiers, Pierre; Paulet, Timothy Guy; Harris, Jean (1 August 2023). "A systematic conservation plan identifying critical areas for improved chondrichthyan protection in South Africa". Biological Conservation. 284 110163. Bibcode:2023BCons.28410163F. doi:10.1016/j.biocon.2023.110163.
  40. ^ Dulvy, Nicholas K.; Simpfendorfer, Colin A.; Davidson, Lindsay N. K.; Fordham, Sonja V.; Bräutigam, Amie; Sant, Glenn; Welch, David J. (5 June 2017). "Challenges and Priorities in Shark and Ray Conservation". Current Biology. 27 (11): R565 – R572. Bibcode:2017CBio...27.R565D. doi:10.1016/j.cub.2017.04.038. PMID 28586694.
  41. ^ Faure-Beaulieu, Nina; Lombard, Amanda T.; Olbers, Jennifer; Goodall, Victoria; da Silva, Charlene; Daly, Ryan; Jordaan, Gareth; Kerwath, Sven E.; Kock, Alison; Mann, Bruce Q.; Murray, Taryn S.; Albano, Patricia; Cliff, Geremy; dos Santos, Natalie A.; Gennari, Enrico; Hammerschlag, Neil; Bester-van der Merwe, Aletta E.; Watson, Ralph; Andreotti, Sara; Bernard, Anthony T. F.; Cowley, Paul D.; De Vos, Lauren; Drobniewska, Natalia; Elston, Chantel; Fallows, Chris; Rogers, Toby D.; Smith, Grant; van Staden, Michaela; de Villiers, Pierre; Paulet, Timothy Guy; Harris, Jean (1 August 2023). "A systematic conservation plan identifying critical areas for improved chondrichthyan protection in South Africa". Biological Conservation. 284 110163. Bibcode:2023BCons.28410163F. doi:10.1016/j.biocon.2023.110163.
  42. ^ Faure-Beaulieu, Nina; Lombard, Amanda T.; Olbers, Jennifer; Goodall, Victoria; da Silva, Charlene; Daly, Ryan; Jordaan, Gareth; Kerwath, Sven E.; Kock, Alison; Mann, Bruce Q.; Murray, Taryn S.; Albano, Patricia; Cliff, Geremy; dos Santos, Natalie A.; Gennari, Enrico; Hammerschlag, Neil; Bester-van der Merwe, Aletta E.; Watson, Ralph; Andreotti, Sara; Bernard, Anthony T. F.; Cowley, Paul D.; De Vos, Lauren; Drobniewska, Natalia; Elston, Chantel; Fallows, Chris; Rogers, Toby D.; Smith, Grant; van Staden, Michaela; de Villiers, Pierre; Paulet, Timothy Guy; Harris, Jean (1 August 2023). "A systematic conservation plan identifying critical areas for improved chondrichthyan protection in South Africa". Biological Conservation. 284 110163. Bibcode:2023BCons.28410163F. doi:10.1016/j.biocon.2023.110163.